The instant invention relates to buckle chute folders used for folding one or more sheets of paper, and more particularly to the exit rollers used with such buckle chute folders.
Buckle chute paper folders employing folding rollers are well known. The sheet of paper is fed by a first pair of feed rollers up into a buckle chute, which stops the forward progress of the paper sheet and causes a buckle to be formed. The buckle is then forced to enter the nip of a pair of folding rollers which impart a crease in the buckle. The folding rollers then continue to feed the folded sheet of paper toward a pair of exit rollers, whose nip is invariably not in the path of the paper being fed from the folding rollers. In order to change the direction of the path of travel of the folded paper, a curved guide or chute is employed to direct the folded paper toward the nip of the exit rollers. With today's demand for high throughput in folding machines, it is becoming common practice to fold a plurality of paper sheets simultaneously.
Typically, the exit rollers discussed hereinabove are formed from a rubber, generally a urethane, and as the plurality of folded papers leave the pair of folding rollers the bottom sheets tends to drag on the chute and the fold tends to open up; the top layer of the outermost sheet begins to pucker up because it is constrained in a shorter distance than the bottom layer between the folding rollers and the exit rollers. As the plurality of folded sheets approaches the exit rollers, the top or outermost sheet is contacted by the upper exit roller which feeds it ahead of the other folded sheets, resulting in the top or outermost sheet receiving a second crease on its lead edge which then causes problems when the plurality of folded paper sheets are inserted into an envelope located downstream.
Thus, the instant invention provides a unique construction for the exit rollers which obviates the problem discussed hereinabove and permits a group of folded paper sheets to enter the exit rollers of the buckle chute folder without a second crease being formed on any of the folded paper sheets.